Difference Between Eructation and Flatus

Eructation and flatus are the cases that usually occur after meals when the gastric cavity is filled with food. Eructation is the sound that is generated by the mouth due to the removal of entrapped gas from the stomach or esophagus, whereas, on the other hand, flatus is the sound that is generated by the distal part of the body due to the release of the entrapped gas from the stomach or intestine.

Eructation vs Flatus

The main difference between eructation and flatus is that eructation is the sound that is produced when the gas is present or entrapped in the stomach or the gastro interview tract is removed from the mouth. While flatus is the sound produced due to the release of the entrapped gases from the distal part of the stomach and intestine.

Eructation vs Flatus

Eructation is also referred to as the action of burping or belching in general terms. Eructation occurs because of the aerophagia in the upper digestive tract. The word ‘eructation’ is more of a technical term and therefore it is most commonly used in medical or scientific purposes and it is mostly replaced with the word ‘burp’ in day-to-day lives.

The term ‘flatus’, also referred to as flatulence. It is the sudden expulsion of the gas that is entrapped in the stomach, gastrointestinal tract, or intestine from the distal part of the body. Too much flatus or flatulence is an indication of the disorder of the disease of the digestive tract.

Comparison Table Between Eructation and Flatus

Parameters of ComparisonEructationFlatus
Route of expulsionExpelled from mouthExpelled from the flatus
Gas entrapped inEsophagus, upper stomach or GITLower GIT or intestine
Other terminologiesBurp and blechFlatulence
Effect on healthNot related to any serious disordersCan provide insight about the mild to severe disorder or disease present in the body
OdorUnpleasant to odorlessFoul to unpleasant
OccurrenceMostly occurs after the mealOccurs anytime during the day

What is Eructation?

Eructation is the term that is mostly used for technical, medical, or scientific purposes to demonstrate the sound that occurs due to the expulsion of the gas that is trapped in the esophagus, stomach, and upper respiratory tract.

It generally occurs after meals when the food causes the gastric cavity to get filled from the esophagus to the stomach i.e. aerophagia. The food causes some void spaces in between and the chewing action (mostly chewing food with keeping the mouth open) causes the air to get in and this air then gets trapped between the void spaces created by the food in the digestive tract.

When the peristalsis moment takes the food to the stomach, the contracting movement of the esophagus creates pressure on the inside wall thus forcing the air to get released from the digestive tract. This sudden force due to the peristaltic movement results in the expulsion of the trapped air or gas.

This expulsion is known as eructation which gets the air released outside the body with a sound to it (as when any sudden force is applied over the trapped air, it tries to escape with noise from the closed environment).

Eructation can sometimes, also be used to express the violent or sudden expulsion of fumes from the volcano or the geysers.

What is Flatus?

Flatus is the expulsion of the trapped gas from the distal or lower part of the body i.e. from the end of the digestive tract or the alimentary canal. Flatus is also known as flatulence. Flatus can be expelled as a voluntary action or it can be an involuntary action.

It occurs when the digestion process is complete and the food is in the intestine for the excretory process. It is resulted due to the entrapment of the gas or air in the intestine. This entrapped gas can be formed due to various reasons some of which include improper digestion, the effect of diet, health conditions, genetic conditions, sleep disturbance, etc.

Many times, if the flatus is present in the body and not expelled outside, this can result in heartburn or acidity. If still there is difficulty in the expulsion of gas or flatulence, then it can lead to serious health issues including heart attacks. Flatus with the softer stools or persistently fluid is associated with gluten absorption or a celiac condition.

Several people suffer from excessive eructation or flatus which may not always be associated with diarrhea. The treatment for this is focused on reducing the occurrence of these symptoms.

Main Differences Between Eructation and Flatus

  1. An eructation is the sound that gets released from the mouth due to the air or gas entrapped in the stomach or the esophagus after the meal, while, flatus is the sound due to the expulsion of gas of the intestine from the distal or the lower part of the body.
  2. An eructation is mostly an involuntary type of action occurring when the food passage to the stomach is full, however, flatus can be a voluntary type of action or an involuntary type of action.
  3. An eructation generally occurs after the intake of the meal, whereas flatus occurs after the digestion process is completed.
  4. In eructation, the gas entrapped in the esophagus or the stomach is released while flatus, the gas entrapped in the intestine is expelled.
  5. Eructation is mostly due to the peristaltic movement that creates a force on the air trapped in the upper digestive tract, while flatus is due to the pressure of the excretory substance in the intestine.
  6. Eructation is mostly odorless to sometimes with an unpleasant smell. But flatus is associated with a very foul and unpleasant smell.


Eructation and flatus, both terms occur due to the release of the expulsion of entrapped gases from the body. The difference between them is the route from which the gas is released. In eructation, gas is released from the mouth, and as flatus, the gas is released from the distal part of the body.

Eructation is caused due to the presence of excess air in the upper digestive tract also known as aerophagia which can be because of an excessive chewing action, chewing gum, sleeping with mouth open, eating too fast, smoking, talking while eating, etc.

Flatus can be caused because of reasons like digestive disorder, diet, change, inappropriate sleep routine, excessively spicy food, daily routine, etc, and in diarrhea, flatus is caused due to lactose intolerance. The foul smell of flatus is due to the traces of impurities like hydrogen, Sulphur, etc. present in it.


  1. https://pediatrics.aappublications.org/content/117/6/e1249.short
  2. https://www.tandfonline.com/doi/abs/10.3109/00365529709002985
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